The present invention relates generally to medical devices and methods, and more particularly to the construction and use of a sterility barrier that allows non-sterile apparatus to be inserted into a lumen of a previously inserted catheter (e.g, a flexible catheter or rigid cannula) without contaminating the patient and while maintaining a sterile field around the exteriorized proximal end of the catheter.
In modern medical practice, and particularly in the fields of interventional cardiology and interventional radiology, it is sometimes desirable to insert non-sterile apparatus (e.g., an imaging apparatus, scope, sensor, emitter, rotating drive member, etc.) into a sealed lumen of a sterile catheter or cannula that may have already been placed in a blood vessel or other anatomical conduit of a patient""s body. Such insertion of the non-sterile apparatus may be problematic due to the need to maintain a sterile operative field around the exteriorized proximal portion of the catheter and to prevent introduction of microbes into the blood or body of the patient.
Examples of some types of procedures in which it may be desirable to insert non-sterile apparatus (e.g., an imaging apparatus, scope, sensor, heater, cooler, sensor, drive member, etc.) into a sealed lumen of a sterile catheter that has been placed in a blood vessel or other anatomical conduit of a patient""s body include, but are not necessarily limited to, intravascular ultrasound imaging (IVUS) procedures, balloon angioplasty procedures, stent implantation procedures, atherectomy procedures, embolectomy procedures, and various interventional procedures wherein puncture tracts or channels (e.g., bloodflow passageway(s)) are formed between blood vessels, or between a blood vessel and another target location, using transluminally advanceable tissue penetrating catheters as described in U.S. Pat. Nos. 5,830,222 and 6,283,951. These relatively new procedures include percutaneous, transluminal techniques for bypassing obstructions in coronary or peripheral arteries through the use of the adjacent vein(s) as in situ bypass conduit(s), and other means of revascularizing oxygen starved tissues or delivering therapeutic substances to vessels, tissue and other organs. As explained in U.S. Pat. Nos. 5,830,222 and 6,283,951, some of these procedures may be performed by a vein-to-artery approach wherein a tissue penetrating catheter is inserted into a vein and the desired arterio-venous passageway is initially formed by passing a tissue penetrating element (e.g., a flow of energy or an elongate penetration member) from a catheter, through the wall of the vein in which the catheter is positioned, and into the lumen of an adjacent artery. Alternatively, some of these procedures may be performed by an artery-to-vein approach wherein the catheter is inserted into an artery and the desired arterio-venous passageway is initially formed by passing a tissue penetrating element (e.g., a flow of energy or elongate penetration member) from the catheter, through the wall of the artery in which the catheter is positioned, and into the lumen of an adjacent vein. In addition, it may be advantageous to direct a penetrating element directly into other anatomical structures such as the myocardium, pericardium, chamber of the heart or other organs to deliver a therapeutic agent to the target location, to implant an electrode, sensor or other device at the target location, or for other reasons as described in U.S. Pat. No. 6,283,951.
One factor that may give rise to the desirability of inserting a non-sterile apparatus into a previously-inserted sterile catheter is expense. Indeed, many types of interventional catheters and other medical apparatus are expensive to purchase. When such catheters and other medical apparatus are required to be sterile, they are often times not re-useable, but rather are manufactured as disposable items that may be used only once and then must be discarded. The expense of such single-use, disposable apparatus can result in avoidance of their use by medical practitioners, even in cases where patients may benefit from their use. For example, intravascular ultrasound imaging (IVUS) catheters typically cost between $500.00 to $800.00 each when purchased by a hospital or health-care institution in the United States and are typically supplied as single-use, disposable items. Several published reports have established that the outcomes of coronary stent implantation procedures may be significantly improved by the use of IVUS. see, Goldberg, S. L. et al.; Benefit of Intracoronary Ultrasound in the Deployment of Palmaz-Schatz Stents, J. Am. Coll. Cardiol 1994 October; 24(4):996-1003; de Jaegere, P. et al., Intravascular Ultrasound-Guided Optimized Stent Deployment, Eur. Heart J. 1998 August; 19(8):1214-23; Schiele, F. et al. Impact of Intravascular Ultrasound Guadance in Stent Deployment on 6 Month Restenosis Rate, J. Am. Coll. Cardiol. 1998 August;32(2):320-8 and Balasini, R. et al., Restenosis Rate After Intravascular Ultrasound-Guided Coronary Stent Implantation, Cathet. Cardiovasc. Diagn. 1998 August;44(4):380-6. However, despite this potential benefit to patients, IVUS is not currently used in most coronary stent implantation procedures. The expense associated with the use of IVUS is believed to be the reason why IVUS is not used in more stent implantaion procedures.
Another factor that may give rise to the desirability of inserting a non-sterile apparatus into a previously-inserted sterile catheter is the need for flexibility and/or small diameter of the catheter. For example, in interventional procedures where a catheter must be inserted through highly tortuous blood vessels or into vessels of very small diameter, such as those of the brain, it is desirable for the catheter to be of the smallest diameter and greatest flexibility possible. Because the inclusion of working apparatus (e.g., sensors, drive shafts, wires, ultrasound transducers, etc.) within the body of the catheter can result in increased diameter and/or decreased flexibility of the catheter, it may be desirable to insert such working apparatus after the catheter has been inserted and advanced to its desired location. Sterilization of such working apparatus prior to insertion into the catheter may be difficult or impossible due to the material and/or construction of the working apparatus. Thus, in such cases, it may be desirable to insert the non-sterile working apparatus into the catheter after the catheter has been inserted into and positioned within the patient, without contaminating the patient or the sterile operative field maintained in the area of the site at which the catheter enters the patient""s body.
The prior art has included various apparatus and methods for creating sterility barriers to prevent contamination of patients and/or medical devices, including those apparatus and methods described in U.S. Pat. No. 5,385,495 (Lynn), U.S. Pat. No. 5,775,328 (Lowe et al.), U.S. Pat. No. 4,491,137 (Jingu), U.S. Pat. No. 4,646,772 (Silverstein et al.), U.S. Pat. No. 4,898,178 (Wedel), U.S. Pat. No. 5,341,810 (Dardel), U.S. Pat. No. 5,490,522 (Dardel), U.S. Pat. No. 5,498,230 (Adair) and PCT International Publication Nos. WO84/03034 (Drue et al.), WO97/49337 (Loxe et al.) And WO99/48424 (Lowe et al.). However, none of these apparatus or methods of the prior art are believed to disclose or teach means for inserting a non-sterile elongate apparatus through a sterile field and into a previously inserted sterile catheter, without contaminating either the sterile field or the patient.
Accordingly, there exists a need in the art for the development of apparatus and techniques that will facilitate the insertion of non-sterile apparatus into a lumen of a catheter (e.g, flexible catheter or rigid cannula) without contaminating the patient and while maintaining a sterile field around the proximal end of the catheter.
A device of the present invention generally comprises a) an elongate apparatus (e.g., a flexible catheter, rigid cannula, probe or other apparatus or member) that has a distal portion that is insertable into the body of a mammalian patient and that has an entry port formed proximal to the distal portion, b) a lumen that extends from the entry port into the distal portion of the elongate apparatus, at least the portion of that lumen that resides within the distal portion of the elongate apparatus being sealed such that any microbes that become introduced thereinto will not escape into the patient""s body and c) a generally tubular sterility barrier, one end of which is secured about the entry port such that a non-sterile working apparatus may be passed through the tubular sterility barrier, through the entry port and into the lumen of the elongate apparatus. The sterility barrier is constructed and sealed to the elongate apparatus such that any microbes or other contamination (e.g., lint, dust, particulate matter, residues of chemical agents, parasites, mold spores, other biological matter, etc.) that becomes introduced into the interior of the tubular sterility barrier by such insertion of the non-sterile working apparatus therethrough will remain and be contained therein.
Further in accordance with the invention there is provided a method for using the device of the foregoing character to perform a procedure wherein a sterile field is to be maintained around a site at which the elongate apparatus (e.g., a flexible catheter, rigid cannula, probe or other apparatus or member) of the device enters the body of a mammalian patient. This method generally comprises the steps of a) providing a device of the foregoing character that is sterile, b) providing a working apparatus that is sized to pass into the lumen of the elongate apparatus to perform some desired function from a position within that lumen, c) inserting the elongate apparatus into the patient""s body and establishing a sterile field adjacent to that site, d) positioning the sterility barrier such that it extends through the sterile field with its second end located outside of the sterile field, e) advancing the working apparatus into the first end of the sterility barrier, through the sterility barrier, through the entry port and into the lumen of the elongate apparatus, and e) using the working apparatus to perform its desired function. The steps of this method need not necessarily be performed in the order stated in this paragraph, but rather may be performed in any suitable order that carries out the intended function of the procedure.
Further in accordance with the present invention, examples of types of xe2x80x9cworking apparatusxe2x80x9d that may be inserted through the sterility barrier and into the sealed lumen of the elongate apparatus include imaging apparatus (e.g., intravascular ultrasound imaging apparatus), scopes (e.g., endoscopes, angioscopes), temperature sensors, pressure sensors, stylets (e.g., catheter tip-shaping stylets or stiffening stylets), light sources, light transmitting members (e.g., optical fibers or fiber optic bundles), magnets (e.g., permenant magnets or electromagnets), radiopaque markers, radiation collectors, an x-ray compass as described in U.S. Pat. No. 5,912,945 (DaSilva et al.), vibrating apparatus, ultrasonic apparatus, sonic apparatus, apparatus for delivery of ionizing radiation, apparatus for emitting energy, apparatus for absorbing energy, sensing apparatus, diagnostic apparatus or apparatus for rotational orientation of the catheter and/or longitudinal positioning of the catheter.
Further aspects of the present invention will become apparent to those of skill in the art upon reading and understanding of the examples and specific embodiments described in detail herebelow.